Fig. (1) Neutrino masses m_i as a function of the lightest mass m₁ for the normal hierarchy NH (left panel) and m₃ for the inverted hierarchy IH (right panel). We have calculated the curves for the mean values Δm₂₁² = 7.53 ·10^-5 eV², |Δm₃₁²| ≈ |Δm₃₂²| = 2.44 ·10^-3 eV² for NH and 2.52 ·10^-3 eV² for IH, and for the admixtures | U_e1|² = 0.6803, | U_e2|²= 0.2354 and | U_e3|² = 0.0843 derived from [8]. Also shown is the effective neutrino mass m_ve, the β-spectroscopic quantity defined by Eq. (5), as well as the sum of neutrino masses derived from cosmological measurements. Also depicted is the upper limit of resulting from the latest measurements at Mainz [38] and Troitsk [39] and the expected limit from the upcoming KATRIN experiment [40].